Is Cointreau replacing oranges with grapefruits in their products?

No, Pomelos (Citrus Paradisi) do not replace Sweet and Bitter Oranges in the conception of Cointreau L'Unique, our orange liqueur. 

Cointreau Citrus Series is a new range of products exclusively for bartenders launched by Cointreau. 

Cointreau L'Unique and Cointreau Citrus Series Corsican Pomelo Distillate are two different products using different citrus fruits. Cointreau L'Unique's formula, based on sweet and bitter oranges, remains unchanged.